Credit

Caption

Coloured scanning electron micrograph (SEM) of Bot fly larva (Oestrus ovis). Adult sheep bot flies (Oestrus ovis) do not oviposit (eggs laid in the host by the adult female). Larvae hatch within the female fly; she deposits them in or near the host's nostrils. The larvae have special hooks to anchor in the nasal passages and frontal sinuses. Larvae feed on the mucosal tissue. The larvae remain in the sinuses for 8 to 10 months and then are sneezed out of the nostrils. Fully-grown larvae exit the nostrils and pupate in debris on the soil for 3 to 6 weeks or more, depending on temperature. Magnification: x6 when shortest axis printed at 25 millimetres.